Silyl diol ester as a new selectivity control agent in MgCl-supported Ziegler-Natta systems for propylene polymerization: catalyst structure and polymer properties.

In this study, bis(benzoyloxy)dimethylsilane (SDE) was developed as a non-phthalate selectivity control agent (internal donor (ID) and external donor (ED)) in MgCl-supported Ziegler-Natta (ZN) systems. The impact of SDE as an ID was investigated in regards to chemical composition, morphology, adsorption behavior (using FTIR spectroscopy, WAXD and SEM studies) and the propylene polymerization performance of the catalyst. The results of the adsorption behavior of SDE revealed that SDE, while able to stabilize the electronically unsaturated surfaces of MgCl [(104) and (110)], has a rather high tendency to be absorbed on strongly acidic Mg ions at the corners of these crystals.